Blending in new PostProcess settings via script

A postprocess volume broke the technique I was using before to set depth-of-field postprocess settings. So this is what I do now:

function UpdateDOF()
{
	local PostProcessSettings OverrideSettings;
	local PlayerController PC;

	PC = GetALocalPlayerController();

	// Calculate DOF settings...

	OverrideSettings.bEnableDOF = true;
	OverrideSettings.bOverride_DOF_FocusDistance = true;
	OverrideSettings.DOF_FocusDistance = // ****** calculate DOF_FocusDistance ******
	OverrideSettings.bOverride_DOF_FocusInnerRadius = true;
	OverrideSettings.DOF_FocusInnerRadius = // ****** calculate DOF_FocusInnerRadius ******
	OverrideSettings.bOverride_DOF_FalloffExponent = true;
	OverrideSettings.DOF_FalloffExponent = // ****** whatever you want the FalloffExponent to be ******
	OverrideSettings.DOF_InterpolationDuration = 0.0;

	LocalPlayer(PC.Player).OverridePostProcessSettings(OverrideSettings);
}